Which of the following are correct statements? Check all that apply.
A. The number of protons in an atom's nucleus defines what kind of
atom it is.
B. Atoms are the basic units of matter.
C. The atomic number is the number of electrons an atom has.
D. The number of neutrons an atom has defines what kind of
element it is.

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

In what direction does the medium move relative to the direction of the wave? explain.

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass